Thermoelectric, high-efficiency, water generating device

ABSTRACT

A water generating device utilizing thermoelectric cooling, also known as Peltier technology, for obtaining potable water from ambient air inside or outside a structure or dwelling, having a unique continuous duct for bringing this supply of ambient air to the device and for releasing the air back outside the device after it has been processed. This device includes a cold sink with which the incoming air is cooled below the dew point to condense the existing water vapor. The cooled air is then redirected over the heat sink which increases the efficiency and cooling capability of the device over that of using only the warmer ambient air to cool the heat sink. The rate of air flow is controlled by the variable speed of one or more fans or blowers. The fan or blower speed in turn is controlled by a device that determines the current ambient dew point by measuring the temperature and relative humidity, and the temperature of the cold sink. The incoming air flow is increased or decreased by the fan or blower, to the maximum possible flow rate without excessively exceeding the determined dew point temperature of the incoming air being processed.

FIELD OF THE INVENTION

The present invention relates to a water-condensing apparatus, and moreparticularly, to a thermoelectric device which makes potable water fromthe air.

BACKGROUND OF THE INVENTION

In recent years, it is becoming more useful for people in both officesand in the home to drink bottled water rather than water from a watertap. Countless other situations exist where water is difficult to obtainor where the quality of available water leaves much to be desired. Inmany cases this also creates a need to carry the water from the placewhere it was purchased to the place where it will be used. Accordingly,there have been some attempts to provide on-site water generation toalleviate these problems. Virtually all of these attempts have utilizedmore traditional methods of conventional compressors, refrigerant, andevaporator and condenser coils. Some attempts have been made to extractwater vapor from the air using thermoelectric technology on a smallscale, such as with a closet dehumidifier. All known attempts haveignored the benefit of using cooled air for reasons other than cooling asmall confined area, as is the case with refrigerators found onaircraft.

SUMMARY OF THE INVENTION

The present invention provides a potable water generator designed toproduce potable water from the ambient air using new and existingthermoelectric, sensing, and computational technologies and other knowndevices in a unique combination that safely and efficiently extractspotable water from the ambient air in a wider range of temperature andhumidity conditions than traditional refrigerant-based systems. Thisinvention deals with maximizing the efficiency of the dehumidificationprocess by uniquely utilizing the cooled air to cool the heat sink ofthe thermoelectric device, supplemented, as needed, with additionalambient air passed over the heat sink The invention also deals withcontrolling the air flow in relation to the incoming ambient airtemperature and the temperature of the cold sink as it relates to thedew point.

This invention provides for unique duct means that diverts and utilizesthe cooled processed air to further increase the efficiency of coolingthe thermoelectric heat sink, thereby significantly increasing theefficiency of the device. This duct can be supplemented with additionalambient air to further cool the heat sink as may be required.

This invention provides an air duct that also serves as a means tocapture the condensed water vapor and divert it into the subsequentwater treatment and/or storage in a closed, continuous system.

This invention provides a repetitive means to determine the existing dewpoint of the ambient air and a means to control the rate of ambient airflow over the cold sink, which allows maximum condensation of theexisting water vapor, with the minimum amount of expended energy, andover a wider range of temperature and humidity extremes.

This invention provides a sterile inlet to the treatment or storage area(permanent or temporary) of water condensed from the air by thestrategic placement of an ultraviolet bulb at the water exit from theair duct into the treatment or storage area. This invention alsoprovides a sterile exit from the water treatment system using the samestrategically placed ultraviolet bulb at the water exit point from thetreatment system into the storage area and/or the exit point from thestorage area. On larger models, this may be accomplished with a secondUV bulb.

This invention provides repetitive ultraviolet sterilization of thepretreated water, and again as treated water, using the samestrategically placed ultraviolet bulb, with ultraviolet transmissivetubing. On larger models, this may be accomplished with a second UVbulb.

BRIEF DESCRIPTION OF THE DRAWINGS

Other objects, features and advantages will occur to those skilled inthe art from the following description of the preferred embodiments, andthe accompanying drawings, in which:

FIG. 1 is a schematic side view of an embodiment of the invention. Itdepicts only the features pertaining to this invention. It does not showall of the other features such as water and air filters, ultravioletexposures, power and electrical diagrams, cabinetry, and control panel;

FIG. 2 is a schematic diagram of a preferred embodiment of theinvention;

FIG. 3 is a block diagram of the electronics, sensing and control systemof a preferred embodiment;

FIG. 4 is a top schematic view of an alternative embodiment of theinvention; and

FIG. 5 is a partial schematic side cross-sectional view of anotheralternative embodiment of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Water generating device 30 according to this invention, is shown inFIG. 1. Thermoelectric device 32 has cold sink 36 comprised of a numberof cold sink fins 37 thermally coupled to the cold side of device 32,and heat sink 38 comprised of heat sink fins 39 thermally coupled to thehot side of device 32. Blower means 40 and/or 41 (such as fans) directsa stream of ambient air past cold sink 36 to cool the air below its dewpoint to condense water droplets 42 from the air. This also cools theair. Passage means 34, which may be an air duct, is arranged to directthe air cooled by cold sink 36 past heat sink 38. Since the air iscooled, more heat is drawn away from heat sink 38, which increases theefficiency of device 32, thus extracting or condensing more water from agiven energy input. The air flow is depicted by arrows A, B, C, D, E andF. The water collection, treatment, storage, and delivery are not shownin this drawing for clarity purposes. A supplemental air flow of ambientair over heat sink fins 39 can be achieved with an additional duct airentrance 43 and variable speed fan or blower 44 that blows air in thedirection of arrow F. For clarity their exact positioning is not shown.

A more complete preferred embodiment of the water generating device ofthis invention is shown in FIG. 2, wherein device 28 illustrates thecomponents pertinent to this invention. For clarity, it does not showadditional known features that may be preferred or desired within acompletely successful device.

There is an incoming ambient air inlet 1 and a processed air outlet 3 atthe ends of a continuous air duct 14. Ambient air is drawn into theductwork by variable-speed fan or blower 2 and forced throughout theducting system. It may be supplemented by exit variable-speed fan orblower 4, and/or additional duct air entrance 43 and variable speed fanor blower 44. For clarity their exact positioning is not shown. Enclosedin this air duct is cold sink 5 and heat sink 6. One or morethermoelectric devices 7 are positioned (in parallel and/or series, asdesired) between the hot and cold sinks to produce the temperature losson the cold sink and temperature gain on the heat sink.

As the cooled air leaves the cold sink 5 it is diverted directly overthe heat sink 6 by ductwork diversion 8, which increases the coolingcapability of the heat sink as opposed to the cooling capability usingonly ambient air, which by definition is warmer.

Ductwork 14 has a lower outlet 9 for the water that has condensed andcollected in that area of the air duct. Outlet 9 also serves as an inletto the initial water storage and/or water treatment system 10. The inletto this storage or treatment system 10 is protected by an ultravioletlight 15 which may also serve as a sterile inlet and/or an immediatewater sterilizer by bathing water passing through outlet 9 inultraviolet light. Ultraviolet light 15 can also be used to sterilizeair that enters water storage devices 11 and 16 as water is withdrawnfrom the storage devices. This can be accomplished with an air passagecomprising tubing or piping 22 and 23 with one end in a container andthe other end located such that the end is bathed in light fromultraviolet light 15. In this way, air is sterilized as it enters tubingor piping 22 and 23, thus inhibiting contamination of the water incontainers 11 and 16. Ductwork 14 also may contain ultraviolet bulbs 18and 17 to sterilize cold sink 5 and heat sink 6, respectively, as wellas to sterilize the air while in ductwork 14.

It is necessary that the incoming ambient air be cooled to the dew pointin order to allow the water vapor to condense from this air. Device 12determines the dew point temperature of the inlet air in a known fashionfrom the combined measurements of the incoming air of both temperatureand relative humidity that may exist at any given time. Device 12 willthen control the desired temperature of the cold sink (at least at orbelow the dew point) by determining the cold sink temperature, andcontrolling the volume and speed of the incoming ambient air over thecold sink by controlling, in turn, the operational speed of fan orblower 2, fan or blower 4, and fan or blower 44. A sensor 21 fordetermining the temperature of the cold sink is also useful foraccomplishing this goal.

Ultimately, the treated water will be diverted to a permanent orremovable container 11 from which the user may remove potable water.Container 11 could also be split into two containers, 11 and 16, one ofwhich could dispense hot water, and the other cold water. Thesecontainers, whether one or two in number, and whether permanent orremovable, can be plumbed to any position on device 30, or to a remotestorage area For the provision of cooled and/or heated water, waterheating device 19 could heat the water in the storage container or as itis extracted, and/or water cooling device 20 could be used to cool thewater in the storage container or as it is extracted.

FIG. 3 illustrates the relationships and interactivity between theoperator control panel 43 (with switches 63, 64 and 65), the indicatorpanel 44, the central processing unit (CPU) 42, and additionalcomponents that may or may not be present in their entirety. Operatorcontrol switches 43 may include on/off switch 63, normal operationswitch 64, and efficiency operation switch 65. The system may be enabledto operate in what is called a “normal” mode, and what is called an“efficiency” mode of operation. In the normal mode, operation iscontrolled with an on/off switch. In this case, the unit will operateover a wide range of ambient conditions, and actual water productionrates will vary accordingly. In the efficiency mode of operation, thesystem is programmed at the factory so that it will operateautomatically only when water production rates are at or above the ratesspecified by the programming. For example, the unit may operate onlywhen the dew point is such that the unit can make a specified volume ofwater per specified time period, for example 2 gallons per day. If theconditions are not such that the unit would make 2 gallons per day,while in the efficiency mode of operation the unit would not run. Thiswill assure satisfactory water production rates at minimal energyconsumption. Typically, when in efficiency mode the system wouldautomatically sample ambient air periodically, for example twice anhour, and as a result either turn on or turn off, as appropriate. If theunit was not running before such sampling took place, the system wouldautomatically turn on the proper blower(s) or fan(s) to provide ambientair to the sensor, and if the dew point was sufficient, the unit wouldthen remain on and begin extracting water. If the dew point wasinsufficient, the unit would shut down until the next sampling period.

The invention contemplates operating the system by means of varioussources of electricity. Peltier devices operate under direct currentsupply. The system may have power conditioning means 71 that providesproperly conditioned power to the unit, shown in FIG. 3 as providedthrough controller 43. The exact manner in which the power is suppliedwould be apparent to those skilled in the art. The system can be enabledto accept power from one or more sources, such a AC power source 72 orDC power source 70. The power source or sources can be line poweravailable at the particular location, or a generator provided for thepurpose, or alternative sources of energy such as solar panels. Unitswith a practical size limitation can be operated by the amount of powerthat can be supplied by solar panels, which allows the system to befully portable and used anywhere without the need for a power supply ora generator.

Other inputs to CPU 42 may include first ultraviolet sensor 50,additional ultraviolet sensor(s) 51, reservoir full sensor 52, storedwater temperature sensor 53 (of which there may be two), reservoir waterlevel sensor 54, cold sink temperature sensor 55, ambient airtemperature sensor 56, ambient humidity sensor 57, air filter efficiencysensor 58, air filter position sensor 59, water filter timed-out sensor60, water filter volume sensor 61, and valid water filter sensor 62.These various sensors and their use in potable water generating systemsare known in the art, for example as disclosed in U.S. Pat. Nos.5,106,512; 5,149,446; and 5,203,989, all incorporated herein byreference.

The outputs of CPU 42 include one or more of the control of water pump48, control of thermoelectric device 47, control of a water cooler means46, control of a water heater means 66, and one or more controls asnecessary to control the state and speed of the fans or blowers 45.Also, indicators 44 are controlled by CPU 42.

When the user deactivates the water generating device with off switch63, all functions cease except the following: all UV lights remain on;the 1st UV sensor 50 continues to monitor for inadequate UVtransmission, which would cause CPU 42 to disable the unit from furtheroperation and signal the remedy to the user on the indicator panel 44;the 2nd UV sensor 51, if present, performs in a similar manner; thewater filter timed-out sensor 60 or the water filter volume limit sensor61 also causes the CPU to deactivate the unit and inform the user on theindicator panel 44 of the reason why; the stored water temperaturesensor(s) 53 causes the CPU to activate the 2nd cooler means 46 to coolthe stored water, and/or to activate water heating means 66, to theirfactory-specified temperature(s).

FIGS. 4 and 5 schematically depict alternative embodiments of theinvention, in which other known components are not shown for claritypurposes. FIG. 4 is a top view of the entrance to air duct 83, in whichis located hot or cold sink 80 with corrugated heat-exchange fins 81projecting therefrom. Corrugated fins contribute to a greater heatexchange rate as opposed to straight fins, due to both their greatersurface area and the air flow turbulence created by the corrugations. Inthis embodiment, the corrugations are parallel to the air flow. Anadditional separate feature that contributes to a greater heat exchangerate is the incorporation onto one or more sidewalls of duct 83 of oneor more projecting artifacts 82, which direct air away from the ductwalls and thereby increase air turbulence, which increases the contactof the air with the fins 81. Projection(s) 82 can take any desiredshape, but are preferably roughly triangular in cross-section to presenta smooth ramp from which the air flow is directed toward the fins.

This flow is shown schematically in FIG. 5. Artifacts 92-94 on the wallof duct 95 redirect air toward fins 91 (which are coupled to hot or coldsink 90), as depicted by air flow direction indicating arrows G throughL. This figure also depicts fins with corrugations that areperpendicular to the air flow rather than parallel to it.

Although specific features of this invention are shown in some drawingsand not others, this is for convenience only as each feature may becombined with any or all of the other features in accordance with theinvention.

Other embodiments will occur to those skilled in the art and are withinthe following claims:

1. A water generating device for extracting water from ambient air,comprising: a thermoelectric cooling device having a cold side and a hotside; a cold sink thermally coupled to the cold side of the coolingdevice, for cooling air that contacts the cold sink; a heat sinkthermally coupled to the hot side of the cooling device, for removingheat from the cooling device; one or more air moving means for directinga stream of ambient air past the cold sink, to cool the air below itsdew point and condense water from the air stream; and passage means fordirecting the air cooled by the cold sink past the heat sink, to removeadditional heat from the cooling device, to increase its efficiency. 2.The water generating device of claim 1 further including dew pointsensor means for determining the dew point of the ambient air.
 3. Thewater generating device of claim 2 in which at least one of the airmoving means accomplishes a variable air speed.
 4. The water generatingdevice of claim 3 further including a controller means, responsive tothe dew point sensor means, that controls the speed of at least one ofthe variable-speed air moving means in response to the ambient air dewpoint, to increase the overall device water generating efficiency, andoperate the device over a wider range of ambient conditions.
 5. Thewater generating device of claim 1 in which the passage means includesan air duct in which both the cold sink and heat sink are housed.
 6. Thewater generating device of claim 5 further including a condensed wateroutlet in the air duct, to allow the condensed water to pass out of theduct.
 7. The water generating device of claim 6 in which the air duct isarranged with a lowest area, and the condensed water outlet is in thebottom of the duct in its lowest area.
 8. The water generating device ofclaim 6 further including an ultraviolet light proximate the outlet, toirradiate condensed water exiting the duct through the outlet, tosterilize the water.
 9. The water generating device of claim 6 furtherincluding a water storage device for holding condensed water passed outof the duct through the outlet.
 10. The water generating device of claim3 further including a temperature sensor for determining the temperatureof the cold sink.
 11. The water generating device of claim 10 furtherincluding a controller means, responsive to both the temperature sensorand the dew point sensor means, that controls the speed of thevariable-speed air moving means, to maintain the cold sink below the dewpoint of the ambient air.
 12. A water generating device for efficientlyextracting water from ambient air, comprising: a thermoelectric coolingdevice having a cold side and a hot side; a cold sink thermally coupledto the cold side of the cooling device, for cooling air that contactsthe cold sink; a heat sink thermally coupled to the hot side of thecooling device, for removing heat from the cooling device; an air ductproviding an air passage past the cold sink and directly to and past theheat sink; at least one variable-speed air moving device for directing astream of ambient air through the air duct past the cold sink to coolthe air below its dew point and condense water from the air stream, andthen past the heat sink, to remove additional heat from the coolingdevice to increase its efficiency; a dew point sensor for determiningthe dew point of the ambient air; a temperature sensor for determiningthe temperature of the cold sink; and a controller, responsive to boththe dew point sensor and the temperature sensor, that controls the speedof at least one of the variable-speed air moving devices, to maintainthe cold sink temperature below the ambient air dew point, to maintainefficient water production.
 13. The water generating device of claim 1further including an ultraviolet light proximate the cold sink.
 14. Thewater generating device of claim 1 further including an ultravioletlight proximate the hot sink.
 15. The water generating device of claim 1enabled for continuous operation.
 16. The water generating device ofclaim 2, further including means for periodically sampling the dew pointof the ambient air.
 17. The water generating device of claim 2 enabledfor an efficiency mode of operation in which the device is operated onlywhen the dew point is at least at a predetermined level.
 18. The watergenerating device of claim 5 in which the air duct defines an ambientair entrance that communicates with the heat sink, and furthercomprising an air moving means in fluid communication with such entranceto allow additional ambient air to be moved across the heat sink, toenhance cooling of the heat sink.
 19. The water generating device ofclaim 18 further including a heat sink temperature sensing means. 20.The water generating device of claim 19 further including controllermeans, responsive to the heat sink temperature sensing means, forcontrolling operation of the additional air moving device.
 21. The watergenerating device of claim 1 further including means to heat storedwater.
 22. The water generating device of claim 1 further includingmeans to cool stored water.
 23. The water generating device of claim 1further including means to change the temperature of water that has beenextracted from ambient air using the device.
 24. The water generatingdevice of claim 1 further including solar power generating meansoperatively coupled to the water generating device for providing powerto operate the water generating device.
 25. The water generating deviceof claim 5 further including one or more air diverters located withinthe air duct to increase turbulence of air flow through the duct, forincreasing the efficiency of the device.
 26. The water generating deviceof claim 1 wherein at least one of the heat sink and the cold sinkcomprise corrugated fins.
 27. The water generating device of claim 26wherein the corrugations of the fins are parallel to the air flowthrough the passage means.
 28. The water generating device of claim 26wherein the corrugations of the fins are perpendicular to the air flowthrough the passage means.
 29. A system for providing sterilized air toa storage container that stores water from a water generating devicethat extracts water from ambient air, comprising: passage means forproviding air flow into the storage container as water is withdrawn fromthe storage container; and an ultraviolet light which bathes the passagemeans in ultraviolet light to sterilize the air as it enters the passagemeans.